1. Field of the Invention
The present invention relates to a method for the control of the traffic of an elevator group.
2. Description of the Related Prior Art
A major problem to solve in the control of an elevator group includes the detection of the peak traffic condition on the main entrance floor or elsewhere. In conventional elevator group control, a peak traffic condition is detected on the basis of the number of departures of elevators with a full load and of the number of calls. However, this data is often obtained at a stage when the peak traffic condition has been continuing for some time or is already over.
In earlier group control systems, the problem is solved on the basis of the numbers of car calls, landing calls and the car load data. For example, if the number of car calls issued from the main entrance floor exceeds a given limit and the cars departing from there are fully loaded, the situation is interpreted as an up peak traffic condition. Similarly, if the number of down-calls exceeds a certain limit and simultaneously the incoming traffic is low and the number of up-calls is low in comparison, then the situation is recognized as a down peak traffic condition.
Patent publication GB-2129971 proposes a control method in which the characteristic traffic modes are formed daily on the basis of the passenger traffic flow data, from which the future traffic is predicted. The characteristic traffic modes are classified on the basis of the volume of upward and downward passenger traffic and the distribution of the traffic between different floors. The traffic modes learn typical data to be used in the elevator control, e.g. door operation times, probabilities of stopping of the cars, load limiations in upward and downward traffic, energy-saving load etc. Statistics on the traffic modes are updated daily according to the time of day and for different week days. However, the amount of data to be stored is very large and the method is suitable only for that specific environment, not for common group control strategies.